Another Transmission Update
01-14-2002, 09:54 PM
#1
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Join Date: Aug 2000
Posts: 2,530
Another Transmission Update
Its been about a month since I blew 2nd gear on my transmission. Yet my car is still not on the road, because I am lazy and have no desire or urge to get back into this car whatsoever. Anyway, since that time, I bought a used transmission that has 16,000 miles on it for $250. I drove 250 miles one way to pick it up, it was this cheap because the case and differential was ruined from the crash it was in. That was no matter, cause I already had a new differential (quaife) and just needed the input and main shafts of the tranny. To help stop my transmission from blowing up again, I had the main and input shafts both cryogenically tempered.
Anyway, I finally got around to working on my transmission today. I was shimming the tolerances for the bearings. Now these are set to the ten-thousandths of the inch, for every .0015" difference in tolerance, a new shim size must be used, thats how precise they must be. My first transmission along with many others here had its differential carrier bearings destroyed due to manufacturing defect of excessive bearing preload (shims too thick). While setting the shims using a precision dial gauge I found that even though in a new case, my previous shims for the differential were dead on, so they were reuseable. However, my next discovery makes me want to question nissan quality control once again.
Out of my two transmissions I had, using a micrometer, I discovered that the shim sizes for both the input shaft and the mainshaft. To my surprise, the two transmissions had the exact same combination of shims in the input shaft as well as the main shaft. Unless I got very lucky and both transmissions had exactly the same tolerances on two different shafts (remember, .0015" tolerance) theres no way that two different cases, with 2 bearings on each shaft are that close together. Upon determining the correct shim needed for the input gauge, the shim size needed for the input shaft was 3 sizes too tight. Once again, excessive bearing preload, but this time in the input shaft. I examined my 67,000 mile tranny. Sure enough there was marks apparent on the races and on the bearing rollers. Nothing spalled yet like the differential bearings noted above, but another 50,000 miles and that wear would certainly show through even more.
Tomorow, I am going to order the proper shims from nissan, then I can put the car back together. Should be back on the road by the weekend.
Anyway, I finally got around to working on my transmission today. I was shimming the tolerances for the bearings. Now these are set to the ten-thousandths of the inch, for every .0015" difference in tolerance, a new shim size must be used, thats how precise they must be. My first transmission along with many others here had its differential carrier bearings destroyed due to manufacturing defect of excessive bearing preload (shims too thick). While setting the shims using a precision dial gauge I found that even though in a new case, my previous shims for the differential were dead on, so they were reuseable. However, my next discovery makes me want to question nissan quality control once again.
Out of my two transmissions I had, using a micrometer, I discovered that the shim sizes for both the input shaft and the mainshaft. To my surprise, the two transmissions had the exact same combination of shims in the input shaft as well as the main shaft. Unless I got very lucky and both transmissions had exactly the same tolerances on two different shafts (remember, .0015" tolerance) theres no way that two different cases, with 2 bearings on each shaft are that close together. Upon determining the correct shim needed for the input gauge, the shim size needed for the input shaft was 3 sizes too tight. Once again, excessive bearing preload, but this time in the input shaft. I examined my 67,000 mile tranny. Sure enough there was marks apparent on the races and on the bearing rollers. Nothing spalled yet like the differential bearings noted above, but another 50,000 miles and that wear would certainly show through even more.
Tomorow, I am going to order the proper shims from nissan, then I can put the car back together. Should be back on the road by the weekend.
01-15-2002, 08:03 AM
#4
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Posts: n/a
Eric, this is indeed some great information! I am not at all familiar with the rebuild of a manual transmission, but I have some familiarity with bearings and pre-load is a critical factor. I think you've come across what could well be the reason why some 4th gen manual transmissions have failed. I would really be curious to match up the build dates for all the known bad trannies. I suspect they all were build in the same period and have the same manufacturing flaw.
Sounds like the manufacturer simply cut some corners and assumed they could throw the same shim stacks on all shafts on all trannies. Bad call for them and us.
Sounds like the manufacturer simply cut some corners and assumed they could throw the same shim stacks on all shafts on all trannies. Bad call for them and us.
01-15-2002, 03:38 PM
#7
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Thread Starter
Join Date: Aug 2000
Posts: 2,530
Alright heres some objective data on my particular case here. The shims I found in both of the transmissions for the input shafts were .0252" and .0268". According to the "Table for selecting input shaft bearing adjusting shim" on page MT-43 of my 1997 Maxima FSM, the tolerance which corresponds to these shims is between .0524"-.0539". I checked the dial indicator for my (it reads to 1/1000 of an inch, so I have to round the ten thousandths of an inch place) was about .047". .047" falls right in the size of .0461"-.0476" which is THREE sizes SMALLER then what was provided in both transmissions. While 3 shim sizes may not seem alot, Frank at www.motorvate.ca measured a 4 size difference in his differential bearings (which are even larger then the mainshaft bearings) caused them to fail. On "Failure Analysis" http://www.motorvate.ca/auto/maxima/...re_summary.htm he writes "I think the pre-load on the bearings was too much. The measurements that I took equaled a shim of .0456 of an inch. The shims that I removed were .0520 of an inch, .0064 too much preload! This means the bearing is being compressed .0064 of an inch too much, and it pounds the tapered rollers and the bearing races until they fail, and the surface flakes off.....
6.4 thousandths of an inch may not seem like a lot, but that is 4 shim sizes too tight. Every .0015 of an inch requires a different shim. Over 60,000 Km this excessive preload pounds the bearing, until it starts to fall apart. (Spalling)"
I ordered the correct input shaft shims today from nissan.
I have yet to measure the mainshaft to see how far off it is, but I plan to do it by a combination of math and Plastigauge (www.plastigauge.com for more info- thanks mardigrasmax). At first when I determined the thickness of the existing shims with a micrometer, I thought "great, I dont have to shim this one" (its alot harder to do then the inputshaft or differential bearings, cause theres no way to access the shaft with simply a dial indicator. But after I discovered that both transmissions had the exact same shims that werent even close to the right ones and after my last experienced with failed differential bearings really made me wonder how far off the mainshaft ones are too.
As for the differential shims, I cannot access the new transmission's shims because the entire area was mangled from the crash the car was in. But- I am willing to bet money that it is the same size as in my original transmission, and possibly the same size of all the maxima owners around this production period. BTW, my car is a 1997 and the new transmission I got is also 1997. Infact my car's VIN is JN1CA21D3VT843254 and the transmission VIN is JN1CA21D6VT208013. From these VIN numbers, we can determine that both cars were made in the Oppama plant. The number after the D are differerent because they are the check digit thats determined by mathematical computation. The only thing thats different is the serial number. I'm wondering if theres any correlation between the VINs and failing transmissions.
Infact if somebody wants to carfax JN1CA21D6VT208013 and show me the results, I'd be curious into seeing what its title history looks like, knowing its a wrecked car.
This is yet another fine example of nissan quality. My take on it is that they cut costs (which they did big time at the end of the 1990s) so they figure heck, if the tranny will last past 60,000 miles when its outta warranty, then they can save the cost of precisely shimming each and every transmission that came out of the plant. Looks like of the transmissions that failed, 1/2 of them are pre60,000 miles and the other 1/2 are post 60,000 miles, but they are all right around 60,000 miles.
6.4 thousandths of an inch may not seem like a lot, but that is 4 shim sizes too tight. Every .0015 of an inch requires a different shim. Over 60,000 Km this excessive preload pounds the bearing, until it starts to fall apart. (Spalling)"
I ordered the correct input shaft shims today from nissan.
I have yet to measure the mainshaft to see how far off it is, but I plan to do it by a combination of math and Plastigauge (www.plastigauge.com for more info- thanks mardigrasmax). At first when I determined the thickness of the existing shims with a micrometer, I thought "great, I dont have to shim this one" (its alot harder to do then the inputshaft or differential bearings, cause theres no way to access the shaft with simply a dial indicator. But after I discovered that both transmissions had the exact same shims that werent even close to the right ones and after my last experienced with failed differential bearings really made me wonder how far off the mainshaft ones are too.
As for the differential shims, I cannot access the new transmission's shims because the entire area was mangled from the crash the car was in. But- I am willing to bet money that it is the same size as in my original transmission, and possibly the same size of all the maxima owners around this production period. BTW, my car is a 1997 and the new transmission I got is also 1997. Infact my car's VIN is JN1CA21D3VT843254 and the transmission VIN is JN1CA21D6VT208013. From these VIN numbers, we can determine that both cars were made in the Oppama plant. The number after the D are differerent because they are the check digit thats determined by mathematical computation. The only thing thats different is the serial number. I'm wondering if theres any correlation between the VINs and failing transmissions.
Infact if somebody wants to carfax JN1CA21D6VT208013 and show me the results, I'd be curious into seeing what its title history looks like, knowing its a wrecked car.
This is yet another fine example of nissan quality. My take on it is that they cut costs (which they did big time at the end of the 1990s) so they figure heck, if the tranny will last past 60,000 miles when its outta warranty, then they can save the cost of precisely shimming each and every transmission that came out of the plant. Looks like of the transmissions that failed, 1/2 of them are pre60,000 miles and the other 1/2 are post 60,000 miles, but they are all right around 60,000 miles.
01-15-2002, 04:49 PM
#8
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Join Date: Aug 2001
Posts: 1,362
I thought you just beat the **** out or your car until it fell apart, guess I was wrong 
I only understood about 1/2 your post, but I get the general idea.
My 98 Maxima 5 speed has almost 80,000 miles on it with no signs of trouble, hopefully I got lucky and got a good one. Unless the previous owner had to do major work, I have only had the car a few months.
My Vin is JN1CA21D0WT******, I think this means it was made in the Oppama plant too
It's the 11th diget (T) that identifies the plant of manufacture, Right? I couldn't find the info on the meaning of the VIN number, I think it is in a stickey somewear.
My carfax ran out a few months ago.
I only understood about 1/2 your post, but I get the general idea.My 98 Maxima 5 speed has almost 80,000 miles on it with no signs of trouble, hopefully I got lucky and got a good one. Unless the previous owner had to do major work, I have only had the car a few months.
My Vin is JN1CA21D0WT******, I think this means it was made in the Oppama plant too
It's the 11th diget (T) that identifies the plant of manufacture, Right? I couldn't find the info on the meaning of the VIN number, I think it is in a stickey somewear.My carfax ran out a few months ago.
01-15-2002, 05:47 PM
#9
Guest
Posts: n/a
Guys, don't focus too much on where your Maxima was manufactured, because I'm almost 100% sure Nissan does not manufacture the transmission. They may make the bellhousing, but not the unit itself. Nissan likely outsources the tranny itself to another company. I don't know who, though. It's rare for a motor car company to actually make their own transmissions.
01-15-2002, 07:13 PM
#10
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Posts: n/a
Just checked my VIN#. It's JN1CA21D8VT865xxx. It's also a 97, and my tranny failed at 70K miles.
Can any other failed 5-speed tranny owners post their VIN#'s? Maybe we can catch some trend here (like the failures only occuring on 97's, or 97's from this serial number to this serial number, etc).
Can any other failed 5-speed tranny owners post their VIN#'s? Maybe we can catch some trend here (like the failures only occuring on 97's, or 97's from this serial number to this serial number, etc).
01-18-2002, 07:48 PM
#12
Senior Member
Join Date: Nov 2001
Posts: 261
This is not good......I have a 97' SE 5spd, 57k miles.
My tranny still works fine, but I am becoming very concerned. I learned to drive stick on this car, so I have ground the gears at least a few times. I do floor it a lot, but I have only peeled out a few times, those times I also power shifted into 2nd. I think I will take it easy for a while, because I do not have any money at all.....
my VIN #: JN1CA21D8VT864***
Which falls right next to the other three listed that have failed.
My tranny still works fine, but I am becoming very concerned. I learned to drive stick on this car, so I have ground the gears at least a few times. I do floor it a lot, but I have only peeled out a few times, those times I also power shifted into 2nd. I think I will take it easy for a while, because I do not have any money at all.....
my VIN #: JN1CA21D8VT864***
Which falls right next to the other three listed that have failed.
01-18-2002, 09:07 PM
#13
Not DAVEB the parts guy
Join Date: Aug 2000
Posts: 8,555
After working for Ford as a consultant, I learned a couple things about the building process of cars. The Maxima is ASSEMBLED at one plant, but the trannies are built somewhere else. There are hundreds of different facilites and OTHER companies that are sourced out for for the construction of automotive parts. At the Ford plant in Kansas City, the truck frames, doors, motors, wheels, tires, trannies, windshields, etc is brought in on train and semi and assembled. The only thing the yproduce is the final product.
Thought I'd just clear that up.
Dave
Thought I'd just clear that up.
Dave
01-20-2002, 01:16 AM
#14
Supporting Maxima.org Member
Join Date: Oct 2000
Location: Columbus, OH
Posts: 1,094
I have a 97 with just under 70k. My tranny will no longer engage in any gear at all. My dealer just says I need a new clutch. I have an extended full warrenty to 100k. Should I have anything else checked out?
I got my quaife and PR mounts back in October when it stopped working.
I am still waiting for my ACT Clutch, UR flywheel, and UR Pully from an "Permanent Maxima.org Resident" ORG member in NY that got my money in October and still posts here daily and has no tiem to send my parts. 3 months without my car working.....
I am in utter despair and $1000 less money. I do not know what to do.
HELP
Mike
I got my quaife and PR mounts back in October when it stopped working.
I am still waiting for my ACT Clutch, UR flywheel, and UR Pully from an "Permanent Maxima.org Resident" ORG member in NY that got my money in October and still posts here daily and has no tiem to send my parts. 3 months without my car working.....
I am in utter despair and $1000 less money. I do not know what to do.
HELP
Mike
01-20-2002, 09:48 AM
#15
Senior Member
Join Date: Nov 2001
Posts: 261
Prodeje79 - Could you post your VIN #? or most of it at least? (Just put X's in the place of the last three numbers or something)
I'm putting together a document containing the VIN #s of all the failed trannies, and the good ones, to look for similarities. Other people are probably doing the same.
- David
I'm putting together a document containing the VIN #s of all the failed trannies, and the good ones, to look for similarities. Other people are probably doing the same.
- David
02-02-2002, 10:23 PM
#17
Senior Member
Join Date: Nov 2001
Posts: 606
If the shims are out of tolerance, would Nissan be liable for shipping defective transmissions? I have a '97 too, my tranny is fine right now at 61K miles....but that could change really quickly!
This is great information! Rarely see such detailed analysis on these forums. Good job!
This is great information! Rarely see such detailed analysis on these forums. Good job!
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